A quantitative analysis of NMR proton relaxation in hen egg albumen and yolk is undertaken to research the causes of quality loss during the first few days of storage and to access the feasibility of an on-line NMR sensor of internal egg quality. It is shown that the change in the transverse relaxation in thick egg albumen mainly results from an increase in proton exchange rate resulting from a pH increase attributed to loss of carbon dioxide by diffusion through the eggshell. The results suggest that the low-field T1 is the best relaxation time indicator of albumen quality.